To explore a new concept of cancer chemotherapy utilizing diphtheria toxin as a chemotherapeutic agent in toxin immune animals. We wish to determine whether it will be possible to use a toxic agent to destroy tumor cells while at the same time using antitoxin antibodies to protect normal cells in the treated individual. BIBLIOGRAPHIC REFERENCE: Rittenberg, M.B., Pinney, C.T., Jr. and Iglewski, B.H. Antigenic Relationships on the Diphtheria Toxin Molecule: Antitoxin Versus Antitoxoid. Infection and Immunity 14:122-128, 1976.